Glass-polishing machine



April 26,' 9 192?.

C. w. DAKE ET Al.

GLAss POLISHING MACHINE' Filed Oc't.l2, 1922 2 Sheets-Sheet 1 1,626,025 Apnl 26 1927' c`:.-w. DAKE ET AL GLASS POLI SHI NG MACHINE Filed Oct. 2, 1922 2 Sheets-Sheet,2

g a. E@ v Q Q 46,

O/E/ c5I if? Patented apr. 26, 1927.

UNITED sTTEs PATENT OFFICE.

CHARLESW. DAKE AND ROBERT S. LEI-IIS, OF CHICAGO, ILLINOIS, ASSIGNOBS TO THE PYLE-NATIONAL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF NEW JERSEY.

GLasS-PoLIsHING MACHINE.

Application llled October 2, 1922. Serial No. 591,756.

Our invention relates to improvements in machines for grinding and polishing glass and particularly to a machme for polishing the outside of a glass reflector bowl for locomotive electric vheadlights and the ike.

These bowls are first cast' and may be parabolic, spherical, conical or may be made up of a combination of such surfaces. The

bowls are ground on the outside to the desired shape but the grinding leaves a certain amount of scratches, tool marks and the like j which must be eliminated by polishin before the bowl is ready to be plated to orm a reflector and one of the major objects of this invention is to. provide a polishing machine and particularly a. polishing element which will polish the bowl, remove the tool marks, and will still retain Without change the original sha e and contour of the outer bowl surface. other object is to provide a polishinprlxliachine which will make use,

o of the polis g element. Other objects will appear from time to time in the specification.

diagrammatically drawings wherein Fig. 1 is a side elevation with parts broken away of the polishing machine,

`Fig. 2 is an upper plan view of the supporting and drivin mechanism for the polishing pad or memer,

Fig. 3 is a section on an enlarged scale through such polishing pad.

Like parts are indicated by like characters `in the drawin A is a machine ged or basey carried-on the legs A. Pro'ecting upwardly from it is the tall bearing racket A2, and intermediate bearing bracket A", and a head bearing bracket A. The brackets A2 and A* are provided with the usual form oi?l bearinos v A and A6. in which-the houow Spindle 1 is mounted. Thishollow spindle carries a sleeve .As rotatably mounted thereon which carries at one end a miter gear lA" in mesh with a miter pinion A1 onv a suitable drive shaft. At the other end of the sleeve is a clutch A11 adapted to en disc A12 splined on the shaft .f

in the accompanying ie a clutch eld in op- Our invention is illustrated more or less` erative engagement with the .disc A11 by the spring A1a and adapted to be thrown out of l.

engagement by lever A14. controlled by handle A1".

B is a chuck plate carried by shaft B2 is a bracket which carries-the coupling B3. Leading into this couplingis a pipe B4 communicating with any suitable vacuum pump or exhauster. B5 is a short pipe leading `from the coupling B3 to and commumcating with the end of the hollow shaft AI so that air can be exhausted from 'the'interior of the bowl through the shaft, coupling and pipe ,to the vacuum pump not shown.

There is a worm C keyed to the shaft AT and in mesh with a worm wheel C1 on the gear shaft C2. The gear Cs `is in mesh with a pinion C4 on the pinion shaft C5.' C6 is a miter inion on this shaft in mesh with a pinion 7 on the inclined shaft Cs which shaft terminates in a pulley C.

The polishing pad is made up of the circular cup D having just inside its periphery the outwardly projecting ange D1 to form a lenticular bowl-like chamber closed on its outer sides by the rubber diaphragm D2 and the felt polishing pad D3. This diaphragm and polishing pad pass around the flange D1 and are tightly clamped against the face of the disc, by means of the annular ring member D, which is held tightly against the feltand rubber by means of the bolts D, v'there' beinga packing washer D" between the felt and rubber elementsI beneath the clamping ring so as to make a permaaov v causes the surface of 'the pad to conform absolutely to the previously arranged contour of the bowl and therefore as the polishing continues no change in shape of the bowl can takelplace because the pressure of the various portions of the pad where they press upon the bowl is always the same for every unit of area.

E is a stub shaft upon which the member D is mounted. It terminates at the other end in a belt pulley E1. E2 is a hub having an anti-friction lining E3 and surrounding the shaft E. -Projecting laterally from this hub are the trunnions E4 pivoted in the frame El5 so that the shaft E may swing in a plane )parallel with the longer axis of theframe 5. The frame E5 is itself pivotedon the stirrup E6' which vin turn is mounted on a bracket E7 on the supporting frame .E2 which latter frame is rigidly mounted on base A and also serves as a guide and support for the clutch lever handle A15. E. is a belt passing over the pulleys C and E1 so that when the shaft A7 is rotated to` rotate the bowl the polishing pad is also rotated in engagement with the bowl, thus bringing various portions of the polishing pad and the bowl into engagement one with the other and insuring the proper operation of the polishing element. E10 is a lever projecting outwardly from the frame E5 so that a weight may be applied to increase the pressure of the polishing element if that is desired'.

F is a semi-cylindrical shield supported on the bracket arms F1- from the frame A. It is closed'at the ends and encloses the lower half of the bowl and the chuck and comes up above the lower extremity of the polishing pad.

It will be. evident that while we have Shown in our drawings an operating'device still many changes might be made in the size, shape and arrangement of our invention without departing materially from the spirit thereof,and we wish, therefore, that our drawing be regarded4 in a real sense as diagrammatic.

We have shown the'inflatable receptacle adapted to be .filled with air. Obviously, itmight be inflated with gas, water, or oil or any othersuitable fluid or liquid, though for its convenience air is the preferred medium. We have used in the claims pneumatic. It is to be understood that the lterm pneumatic in a broad sense is not merely limited to air but directed to filling the receptacle withv any liquid .under pressure tov give the desired equalizing result.

Theuse and operation of our invention are as follows:

The reflector bowlswhich are first cast,-

' preferably by a process similar to die castmg, -Ato give them the approximate size and 'shapeare ground to correct shape on any` suitable grinding machine which forms no part of -my present invention. These bowls ordinarily have a central aperture through which the lighting element is introduced into the searchlight. This hole is closed by a suitable removable plug. The open face of the bowl is then brought into engagement with the chuck disc which at that time is at rest, and the air is sucked out from the space between the bowl and the plate to clause the bowl to be held in position by atmospheric pressure. The polisher frame which prior to that time is held away from the bowl is lowered until the pad itself engages the outer surface of the bowl. The

driving belt is then put in place and the clutch is thrown to start rotation of the shaft. This rotation of the shaft causes the bowl to spin. It alsol causes the polishing pad to spin or rotate in engagement with the bowl and this rotation of the bowl and the pad continues until the polishing has been Y completed. l

The use of the air inflated polishing pad makes it possible to have the pressure of the' polishing element against the bowl the same at every point. It enables the rather thin, flexible polishing surface to correctly conform to the contour of the bowl and insure that as polishing takes place the shape of the bowl will not change. It also insures that the tool marks left on theI bowl by the grinding process will. not be expanded or increased as might be the case if a rigidly backed polishing surfaoe/ were used. lWe claim:

1. A pad for glass polishing machines and the like comprising a rigid flanged circular plate, a iexible impervious diaphragm closing the bowl formed by the plate and flange a flexible by the impervious iaphragm, the periphery of the pad and the diaphragm extending beyond andenfolding the iiange, an annular ring encircling the outer periphery of the plate and -having an inwardly extending flange parallel with the face of the plate, the

polishing pad supported' inner diameter of said flange being greaterv the flange, the inner diameter of the flanged portion of the ring being greater than the outer diameter of the bowl, a flexible impervious diaphragm closing the. bowl, a iexible polishing pad supported by f' the impad and the diaphragm on the bow pervious diaphragm, the outer edges of diafphragm and. ad extending around the edge of the fbowl etween the inner edge of the ange on the ring and the uter edge of the bowl and extending laterally between the 'surface of the bowl flange and the surface of the ring lflange and means for drawing the together and to clam vand the Itwo 'flanges Eoi'de a gas tight chamber formed by the 10 w1 and the diaphragm.

Signed at Chicago, Illinois, this 23rd day of September, 1922.

CHARLES W. BAKE. Signed at Chicago, Illinois, this 23rd day of September, 1922.

ROBERT S. LEVIS. 

